Understanding Elementary Shapes-Solutions Ex-5.1

CBSE Class –VI Mathematics
NCERT Solutions
Chapter 5 Understanding Elementary Shapes (Ex. 5.1)

Question 1. What is the disadvantage in comparing line segments by mere observation?
Answer: There may be a chance of error due to improper viewing.
Question 2. Why is it better to use a divider than a ruler while measuring the length of a line segment?
Answer: It is better to use a divider than a ruler, because the thickness of the ruler may cause difficulties in reading off her length. However, divider gives up the accurate measurement.
Question 3.Draw any line segment, say AB¯. Take any point C lying in between A and B. Measure the lengths of AB, BC and AC. Is AB = AC + CB?
[Note: If A, B, C are any three points on a line, such that AC + CB = AB, hence we can be sure that C lies between A and B.]
Answer: Yes.

AB = 6.5 cm, AC = 3cm, CB = 3.5 cm
AC + CB = 3 cm + 3.5 cm = 6.5 cm = AB
Question 4.If A, B, C are three points on a line such that AB = 5 cm, BC = 3cm and AC = 8 cm, which one of them lies between the other two?
Answer: AC¯ is the longest line segment, thus B is the point between A and C.
Question 5.Verify whether D is the mid-point of AG¯.

Answer: AD = 3 units, DG = 3 units
AD = DG.
Thus, D is the mid-point.
Question 6. If B is the mid-point of AC¯ and C is the mid-point of BD¯, where A, B, C, D lie on a straight line, say why AB = CD?
Answer: B is the mid-point of AC¯.
 AB = BC ……….(i)
And C is the mid-point of BD¯.
 BC = CD ……….(ii)
From eq. (i) and (ii),
Question 7.Draw five triangles and measure their sides. Check in each case, of the sum of the lengths of any two sides is always less than the third side.
Answer: Yes, the sum of two sides of a triangle is always greater than the third side.
 apply Pythagorean theorem to find the hypotenuse i.e 14.14cm